Goblins capture so many kids that eventually they're overwhelmed by the different races that outnumber them. They don't have children and are immortal and so slowly die off, leaving friendly (or not so friendly) races behind. I remember being at war with six races at once, the elves, humans, cats (yes, cats as a race), wizards, orcs and merpeople (who suffocated instantly when they got onto the map, which is hilarious).
If you haven't made a mermaid death camp, you have not lived.
